Originally Posted by mprelaw

Yup. The marathon is still a lot harder than a century. I ran my marathons (under 3 hours) at 148. I was about 152 for my first solo century. There were a couple of marathons where the last 6 miles were a death struggle.

Here's the thing---you can't ever coast when running. Running downhill isn't coasting. It beats up your hamstrings worse than running flats or uphill. You can go down to the small ring and spin easy to finish a century, if you bonk. For a runner, you run at whatever pace in a race. Say 6 minutes/mile. Try running at 8 minutes/mile and your form goes all to hell.

I ran my marathons in my 20s. I'll be 60 next week. Centuries are still easy. I've done 100/75 back to back, with the last 10 miles of the 75 uphill and into the wind. It was still easier than any marathon I ever ran.

If you're a trained swimmer, swimming is the easy part of a tri.